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Surface corrosion

M

Maxrate

Well Known Member
Patron
So I finally got around to pulling the blue protective coating off the wing skins and this south Texas moisture left several areas of surface corossion underneath. Locally they only sell gallons of etch and alodine for over 100$. I probably only need a cup of each. Question is, is there any other method cheaper for getting rid of the corossion. I found that red scotchbrite takes it almost completely out.
Still kicking myself....:mad:
 
If it is white ish tin worm, get some Alumiprep from Spruce. There are other similar products in the catalogue.

Basic phosphoric acid surface cleaner. Use grey or red scotch with gloves on and then rinse off.

After that, just spray some rattle can over the area and move on.

We had similar on ours and all was well after that.
 
How far are you from completing the aircraft? If it were me, knowing that the whole exterior has to be prepped for paint, I'd be inclined to let it go if paint was going to happen in the near future.
 
Why not just scuff it with a scotch brite pad, then spray it with primer until you are ready to paint? Thats what I would do.
 
Maxrate said:
So I finally got around to pulling the blue protective coating off the wing skins and this south Texas moisture left several areas of surface corossion underneath. Locally they only sell gallons of etch and alodine for over 100$. I probably only need a cup of each. Question is, is there any other method cheaper for getting rid of the corossion. I found that red scotchbrite takes it almost completely out.
Still kicking myself....:mad:
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Call your local auto paint retailer. All of the ones around here carry quarts of etch and alodine, and the cost isn't crazy.
 
Believe it or not none of the local auto paint suppliers have it in quarts only gallons, which puts it slightly over $100 to fix the small bit of corrosion. I haven't started the fuselage yet so it will be a while before the plane is together and painted. Was hoping to find a cheaper way of taking care of the corrosion Guess I'll just have to pay the piper. Thanks all.
 
Local Ace Hardware

Ospho is the same stuff. Used it when I striped and repainted our 182 several years ago. Around $15 bucks per quart and lasts forever!

http://www.ospho.com/
 
Last edited:
Maxrate said:
Believe it or not none of the local auto paint suppliers have it in quarts only gallons, which puts it slightly over $100 to fix the small bit of corrosion. I haven't started the fuselage yet so it will be a while before the plane is together and painted. Was hoping to find a cheaper way of taking care of the corrosion Guess I'll just have to pay the piper. Thanks all.
Click to expand...

Ordering alodine from Spruce is just about as low cost as your are going to get for a quart or gallon. I bought the Iridite powder and make it for $6 a gallon, but that is not for everyone and it is a hazard.

The surface has passivated already so you are probably just as well off to leave it until you are flying and/or ready to paint. If it has eaten through the surface coating, then that is another matter.

I like having alodine on hand for all the small parts that are a pain to prime and it is very quick to do. They look nice too. Just keep your alodine supply out of the sun.
 
Bill, you are correct on the cost from Spruce. It's the shipping that kills you. For me to Houston they want 61$ FEDEX ground :eek: :eek: I think I'll try the Ospho product and see how it works. I found a qt at the local ACE. A call to the factory and they said will work fine on aluminum.
 
Corrosion repair

If it's the usual small spot, why not scuff with maroon scotchbrite to remove the corrosion, clean and use an alodine pen then dab some primer?
What does Vans say?
 
Corrosion prevention during build

One thing I do that seems to help, is after I have cleaned up a part and deburred it, but before I join it to another part, I sponge brush on some thin wash primer. In my case I use Dupont Variprime 615S. If it is an internal part, I will scotch bright it, then clean with a diluted water based detergent/degreaser spray bottle that I keep handy. If it is an exterior skin, I don't scotch bright prior to wash primer, in case anyone wants to go with a polished exterior in the future. The thin wash primer coat also protects from scratches kind of like the blue plastic. The wash primer also protects if there is a long delay in construction. When you mix thin, and in small amounts, you use very little material, and it dries quick, so to me it seems easy and inexpensive.

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Why not try one of the EAA chapters in your area like chapter 12 surely they know somebody that has some you can buy a little bit from.
Bill
 
Maxrate said:
Bill, you are correct on the cost from Spruce. It's the shipping that kills you. For me to Houston they want 61$ FEDEX ground :eek: :eek: I think I'll try the Ospho product and see how it works. I found a qt at the local ACE. A call to the factory and they said will work fine on aluminum.
Click to expand...

Mark, the Ospho is only for the etching/dissolving of surface oxides. Send me an email with your address and I will send you a gift.
 
Spruce

I wanted to make a correction. I received a polite email from Jim Erwin, president of Aircraft Spruce stating that I might want to review the shipping cost. After inputting the info for a quart of etch and alodine to Houston the cheapest shipping came up as 14.50$. I don't know how I missed that number. Two day air was 61$ but if you don't need it immediately ground is definetly affordable. A big shout out to Spruce and their customer service shines again! Thanks Jim.
 
Spruce has had issues over the last year with whacky freight rates.

If you see something that just looks wrong - get in touch with them and they usually say - oops !
 
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